After firelapping a .357 BH, I got out the chrony for some .45 Colt tests. Just putting some observations out here.

I have been using IMR 4227 for a little while with regular primers CCI-300. It shoots well in the Vaquero. I decided to use Magnum primers as I read that this powder should be used with such. What a difference! The velocity is now in-line with what I expected. Here are the results

Note that the shells were a little sticky on extraction. Not bad, but I might back off a little bit on this load.

Also I put this here as a 'WARNING'. I am not on the 'bleeding' edge of pressures for the .45 Colt, so all is well with these loads. But if I was working on a very top end Ruger Only Load, changing the primer could have been a problem. The results speak for themselves!!!

As you can see it added 147fps to the velocity and the standard deviation was cut in half. You can sure feel the difference in your hand too! I didn't do any accuracy testing as I was shooting over a chrony today... That will come next!

FWIW, I also tried a Green Dot load today as well over the chrony. Again no real accuracy tests, just wanted some speed numbers today.